EOIR Constraints

In the EOIR constraints category, you can set a signal-to-noise ratio (SNR) on an EOIR sensor. To make the SNR constraint effective, you must select at least one of the limits (Min or Max) in the Constraint Properties area. The SNR constraint defaults to having Min selected with a value of 1. You can opt to exclude time intervals that satisfy the SNR constraint.

For point source targets, SNR is computed as:

SNR_Point = E_Target * ENSQ / E_TotalNoise

where,

E_Target is the total irradiance of the target.

ENSQ is the peak response of the system point spread function contained in a single pixel.

E_TotalNoise is the noise per pixel, including sensor noise, target shot noise, and background shot noise.

For area targets, SNR is computed as:

SNRArea = (Ön)* |L_Target - L_Background| / L_TotalNoise

where,

The quantity n is the number of target pixels.

L_Target is the average radiance of the target.

L_Backgroundis the average radiance of the background.

L_TotalNoise is the average noise per pixel, including sensor noise, target shot noise, and background shot noise.

Probability of target detection is generally a function of the SNR, with the larger SNR corresponding to higher detection probability.